1. Field of the Invention
This invention relates to a tensioning means for ribbon cassette for a typewriter, printer, etc. having a supply spool carrying the unused portion of a printing ribbon and a take-up spool on which the used portion of the ribbon is wound.
2. Description of the Prior Art
In a ribbon cassette for a typewriter, printer, etc., it is necessary to provide a tensioning device for applying tension to the printing ribbon on the supply spool. As the printing ribbon is used, its diameter on the supply spool becomes smaller. If the supply spool is of the type which is movable in one direction, its movement brings about a change in the spring force which applies the tension and thereby in the tension on the printing ribbon. This change disables clear printing.